def main():
    x = int(input())

    if x >= 30:
        print('Yes')
    else:
        print("No")



if __name__ == main():
    main() def main():
    x = int(input())

    if x >= 30:
        print('Yes')
    else:
        print("No") main x = int(input()) x int(input()) int input() input if x >= 30:
        print('Yes')
    else:
        print("No") x >= 30 x 30 print('Yes') print 'Yes' print("No") print "No" if __name__ == main():
    main() __name__ == main() __name__ main() main main() main def main():
    x = int(input())

    if x >= 30:
        print('Yes')
    else:
        print("No") def main():
    x = int(input())

    if x >= 30:
        print('Yes')
    else:
        print("No") main
def main():
    x = int(input())

    if x >= 30:
        print('Yes')
    else:
        print("No")



if __name__ == main():
    main()